Alternating-current electric motor.



Patented Nov. 2|, I899.

C. L. ROSENDVIST. ALTERNATINHGURBENT ELECTRIC MOTOR.

(Application filed Mar. 81, 1898.,

4 Sheets-Sheet I.

(No Model.)

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No. 637,348. Patented Nov. 2|, I899.

C. L. ROSENHVIST.

ALTERNATING CURRENT ELECTRIC MOTOR.

(Application filed Mar. 31 1898.!

(No Model.) 4 Sheets$heet 2.

TN: Norms rrrzns co, momumm, wasnmm'ou, o. c.

No. 637,349. Patented Nov. 2:, I899. c. L. ROSENHVIST.

ALTERNATING CURRENT ELECTRIC MOTOR.

(Application filed Mar. 31, 1896.)

4 SheetsSheei 3.

(No Model.)

25% A flaw ub. 637.349. Patented Nov. 2|, I899;-

c. L. nosanuvlsT,

ALTERNATING CURRENT ELECTRIC MOTOR.

(Application filed Mar. 31, 1898 (No Modal.) 4 Sheets-Sheet 4.

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UNITED STATES PATENT OFFICE.

CONRAD LUDVIG ROSENQVIST, OF BIRMINGHAM, ENGLAND, ASSIGNOR TO VERITYSLIMITED, OF LONDON, ENGLAND.

ALTERNATlNG-CURRENT ELEGTREG MOTOR.

SPECIFICATION forming part of Letters Patent No. 637,349, dated November21, 1899.

Application filed March 31, 1898. Serial No.6'76,020. (to model.) 4

T at /2/0711, it may concern: of a shaft has been obtained and will behere- Beit known that I, CONRAD LUDVIG- ROSEN- inafter more fullyexplained. QVIST, engineer, a subject of the King of Swe- Referring nowmore particularly to Figs. 1

den and Norway, residing at Birmingham,in and 2, my improved armaturesare con- 5 the county of Warwick, England, have instructed with two ormore separate cores, vented new and useful Improvements in or threebeing shownin the drawings,(marked A 1 Relating to Dynamo-ElectricMachinery, of B (3,) secured side by side on the same spinwhich thefollowing is a specification. dle 1. In Fig. 1 the cores are shown oneout Myinventionrelatestodynamo-electricmaside the other in order thatthe position of I0 chinery, and in particular to machines which thearmature-coils may be somewhat more are adapted to be operated either assingleclearly indicated. Each core is wound with phasealternating-current motors or as directcoils 2, and said coils areconnected in shecurrent motors. Some of my improvements cession toasingle commutator 3. The cores are, furthermore, applicable to motorsand A B O are staggeredthat is to say, are ser 5 generators of theordinary type. cured to the shaft 1 in such a manner that The chiefobject of myinvention is to prothe coils 2 thereon are .displacedrelatively ride a single-phase alternating-current motor with regard toeach other, as clearly shown which shall be capable of operatingefficiently in Fig. 1. on circuits of any desired periodicity, which InFigs. 1 and 2 the coils are connected in 20 shall be eifective instarting, and in which the series and in succession, so that any one ofthe current consumption will be regulated in procoils has its endsjoined to coils which are portion to the work done without causing anynot upon the same core as itself. For exfiuctuation in the lightsoperated from the ample, the ends of a coil on a core A are samecircuit. joined to coils on cores B and 0, one on each 25 The chieffeature of my invention consists side. The commutator-bars in amultipolar in an improved construction of dynamo-mamachine arecross-connected in the usual chine armature, and also in a new method ofmanner, as shown in Fig. 1, so that the two winding the field-magnets ofthose alternathalves of the armature will be joined in paring-currentmotors in which two sets of windallel. The coils may, however, ifdesired, be o ings are provided on the field-magnet,whereby so wound asto obviate the necessity for crosswhen a current is flowing in one setof windconnecting the commutator-bars, as shown ings the secondarycurrents developed in the for example, in Figs. 3 and at. other set ofwindings are neutralized. In Fig. 3 the holes through which the coils Myinvention also comprises an improved are wound are shown as being ofdifferent 35 indicatorwhich can be adjusted so thatalamp sizes toindicate on which core of the armashall be lighted or an alarm givenwhen the ture the coilis situatechthelarge slots (marked machine-spindleattains a predetermined A) being in the core A, for example, the nextspeed of rotation. size (marked 5) being in core B, and the My inventionis illustrated in the accomsmallest (6)in the core C. In the development0 4o panying drawings, in Whichof this armature (shown in Fig. 4) theslots Figurelis an elevation, somewhat diagramare of the same size,since the separate cores matical, of a four-pole machine having an arareclearly shown. The winding is as follows: mature constructed and woundaccording to Starting from the commutator-bar 7,the'wind my invention.Fig. 2 is a side elevation of ing passes through a slot 4 on the core A,

45 the same. Fig. 3 is a diagram illustrating then toacommutator-bar 8,diametrically opanother method of connecting the armatureposite the bar7, from the bar 8 to another coils in a ring-armature. Fig. 4: is adiagram slot 4 on the' core A, diametrically opposite i showing thedevelopment of an armature such the first slot. From thence it passes toa comas illustrated in Fig. 3. Fig. 5 is an elevamutator bar 9 nextadjacent to the bar '7, and [00 l 50 tion illustrating myimproved deviceforlight from thence to a slot 5 in the core B next in ing a lamp when adesired speed. of rotation front of the first slot of the core A. Fromslot 5 the winding passes to the commutatorbar lOadjacent to the bar 8,and from thence to a slot 5 on the core 13 directly opposite the firstslot. From the slot 5 the wire passes to a bar 11 adjacent to the hart),and from thence to a slot 6 on the core C; from the slot 6 to the bar 12in front of bar 10, and from bar 12 to a second slot 6 on core C. Fromthis slot the wire passes to a bar 13 next in front of bar 11, and frombar 13 to a slot on the core A, half-way between the first two slotsabovementioned on the same core. Without tracing the winding completelyit will be readily seen that after passing through two diametricallyopposite slots in one core the winding passes through two similar slotson the next core, and then on the next core, the coils being therebyconnected in series. By this construction of armature I increase thedistance between the coils on each core, and thereby the effective polarsurface of the core,without diminishing the total number of coils orcommutator-bars for the entire armature. Furthermore, the number ofslots in one of the cores will be onlyone-half or one-third or less partof the whole number of slots orarmaturecoils.

The machine illustrated in Figs. 1 and 2 is intended for use as analternating-current synchronous motor, and is provided with a pair ofcollecting-rings 531 22. Sue of said rings is joined to onecommutator-segmcnt, and the other of said ringsis joined to acommutatorsegment which is ninety degrees from the first segment, thedifference of potential between said segments being a maximum withafour-pole machine. The points at which the collecting-rings areconnected to the armature will of course vary with the number offield-magnet poles with which the machine is provided.

For conveniently vz'trying the connection of the machine to thesupply-circuit in the method of operation hereinafter set forth I.

provide a switch, (illustrated diagrammatically in Fig. 1,) in which isa base, of any suitable material, and 51 a switclrarm pivoted thereto at52. The base of the switch carries three sets of contacts, (indicated bythe numerals 53 to 62, inclusive.) The supply mains are indicated at 63and G l and are connected through suitable terminals 65 and 66 to theswitch-contacts, the terminal 65 being connected to the contacts and 62and the terminal 66 being connected to the contacts 50 and net winding27, the other end of which winding is connected through the conductors72 and 69 to the commutator-brush The coin tacts (30 and (51 are joinedthrough the conductors To and 74-, respectively, to the brushes 26 and25, which press upon the collectingrings. The switch-arm 51 is providedwith bridge-pieces '75, 70, and 77, which are arranged to connect thecontacts 53 and 54:, 01 and 62, and 59 and 60, respectively, when theswitch-arm is in the position shown in full lines, the bridge-pieces 76and 77 being also arranged to connect the contacts 55 and 56 and 57 and58, respectively, when the switch arm is in the position shown in brokenlines. Normally the switch-arm is maintained in the position shown infull lines by means of a suitable spring 78.

The method of operating is as follows: The mains 63 (it being suppliedwith alternating current, the switch-arm 51 is rotated on its pivot tothe position shown in dotted lines, whereby the terminal 65 will beconnected through the contacts 55 55 and wire to the comm utator-brnsh2i, and the terminal 06 will be connected through the contacts 58 and 57and wire 71 to the end of the magnetizing-coil 27. Alternating currentwill therefore be supplied to the magnetizing-coil 27 and to the commutator through the brushes 2S and 21- an d the armaturetherebycaused torotate. Thespe'ed of the armature increases until synchronism with thegenerator supplying current to the mains (53 (it is obtained, and theswitch-arm being then released the. spring 78 operates to cause it toassume the position shown in full lines in the drawing. In this positionof the arm the terminal (35 will be connected through contacts 62 U1 andthe conductor 74- to the brush 25, and the terminal 06 will be connectcdthrough the contacts 59 60 and conductor 73 through the brush 20, sothat alternating current will be supplied to the armature throiiigh thecollecting-rings. At the same time direct current will be supplied fromthe armature through brush 23, wire (30, wire 68, magnetizing-coil 25),wire (17, switch-contacts and 51, wire 70, and brush 21-, so that thefield magnetism will be maintained. ln operating machines in this mannerthe fieldmagnet coil through which an alternating current passes beforesynchronism is obtained must necessarily be composed of a few turnsonly, while that through which the rectified current from thecommutatorbrnshes passes when the motor is runningin synchronism withthe generator should be composed of a large number of turns. Dillicultyis experienced when running the motor p to synchronism from the factthat the alternating current in the fleld magnet coils induces in thecoaxial coils secondary currents of very high electromotive force, whichmay break down the insulation. To obviate this, I displace one set ofcoils with regard to the other, indicated in Fig. 1, where thealternating-current coils are shown at 27, being wound in slots 28 inthe pole-pieces,while the direct-current coils 29 are wound on thepole-pieces in the ordinary way.

On consid- IIO ceases eration it will be found that the alternatingcurrent flowing in one coil 27 induces a currenton the overlapping coil29. The said coil 29 has also a current induced in it from the nextadjacent coil27 to the first mentioned,and this second induced currentbeing opposite in direction to the first the total effect of the twocurrents will be m'l.

Referring now to Fig. 5, 30 is the shaft of a synchronous motor, 21 and22 being the collecting-rings. 31 is a flexible spring adjustablymounted in a slot 32 in the shaft 30 and secured therein by a set-screw83. One of the collecting-rings 21 is uninsulated on a portion of itsinterior surface when the shaft has attained a certain speed. Thecentrifugal force acting on the flexible arm 31 will cause the same tomake contact through the contact-point 34- with said ring. To the brush26, which bears on the other collecting-ring 22, one terminal of asignal-lamp 35 is connected, the other terminal of said lamp beingconnected to the dynamo-frame and through the bearings with the shaft30, as indicated diagrammatically by the line 86. The action of thisdevice is as follows: hen the speed of the shaft 30 reaches a certainamount, which can be regulated by adjusting the spring 31 in the slot32, the contact-stud at the end of said spring makes oonnection'with thering 21, thereby closing a circuit between the two collecting-rings andthe lamp 35 and lighting said lamp. In place of the lamp any suitablesignal or alarm may be given. Obviously the use of a device similar tothat described is not confined to the shafts of alternating-currentmotors, but may be used to indicate when any rotating shaft has attaineda predetermined speed.

What I claim is- 1. A sin gle-phase synchronous alternating currentelectric motor, whose main field-magnet poles are slotted or perforatednear the inner edge, and are supplied with two sets of windings, onewinding surrounding the whole of each main polar projection, and theother winding surrounding one-half or a part of each of two adjacentmain polar projections, combined with means whereby the latter windingis joined in series with the armature-winding when the motor is startedand replaced by the first-mentioned winding when synchronism isattained, for the purpose specifled.

2. A multipolar dynamo-electric generator or motor having a subdividedarmature-core, each section of said core being supplied with an equalnumber of slots or perforations near the outer edge, and all secured tothe same spindle in such a manner that the slots or perforations in eachsection of the cores are not in line with one another, but uniformlydisplaced relatively to one another, and hav ing coils or windingsplaced in said slots, and connected successively in series with thecommutator-segment in such a way that one end of each coil is joined atthe commutator to the end of another coil on the same core.

3. A sin gle-phase synchronous alternating current electric motor, whosemain field-magnet poles are slotted or perforated near the inner edge,and are supplied with two sets of windings, one winding surrounding thewhole of each main polar projection, and the other winding surroundingone-half or a part of each of two adjacent main polar projections,combined with means whereby the latter wind ing is employed when themotor is started and the first-mentioned winding is employed whensynchronism is obtained, for the purpose specified.

4. The combination with an alternating-current electric motor of a rodpassing through a hole or slot in the spindle and substantiallyperpendicular to the axis thereof, a springarm supported at the end ofsaid rod and a ring coaxial with the spindle and surrounding the rod andarm with which ring the end of the arm makes contact when the spindleattains a predetermined speed, substantially as and for the purposespecified.

In witness whereof I have hereunto set my hand in presence of twowitnesses.

CONRAD LUDVIG- ROSENQVIST.

Witnesses:

FREDERICK WILLIAM LE TALL, LEONARD EDMUND HAYNES.

